Hey aspirant.

See u r from the branch which is having the most no of the applicants for GATE exam. And ur marks are just enough to qualify the exam . It is not sufficient to support u to get admissioned in good colleges for pursuing ur further studies.

About choosing NITS and IITS , it is sorry to say that u will be deprived to be getting admissioned there as ur marks are not so good. On my opinion if u are having good efforts then try next time with much more preparation.

Hope this helped u. Ask if any query 

Good luck